linux/drivers/clocksource/timer-atmel-st.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * linux/arch/arm/mach-at91/at91rm9200_time.c
 *
 *  Copyright (C) 2003 SAN People
 *  Copyright (C) 2003 ATMEL
 */

#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/export.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/atmel-st.h>
#include <linux/of_irq.h>
#include <linux/regmap.h>

static unsigned long last_crtr;
static u32 irqmask;
static struct clock_event_device clkevt;
static struct regmap *regmap_st;
static int timer_latch;

/*
 * The ST_CRTR is updated asynchronously to the master clock ... but
 * the updates as seen by the CPU don't seem to be strictly monotonic.
 * Waiting until we read the same value twice avoids glitching.
 */
static inline unsigned long read_CRTR(void)
{ … }

/*
 * IRQ handler for the timer.
 */
static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id)
{ … }

static u64 read_clk32k(struct clocksource *cs)
{ … }

static struct clocksource clk32k = …;

static void clkdev32k_disable_and_flush_irq(void)
{ … }

static int clkevt32k_shutdown(struct clock_event_device *evt)
{ … }

static int clkevt32k_set_oneshot(struct clock_event_device *dev)
{ … }

static int clkevt32k_set_periodic(struct clock_event_device *dev)
{ … }

static int
clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev)
{ … }

static struct clock_event_device clkevt = …;

/*
 * ST (system timer) module supports both clockevents and clocksource.
 */
static int __init atmel_st_timer_init(struct device_node *node)
{ … }
TIMER_OF_DECLARE(atmel_st_timer, "atmel,at91rm9200-st",
		       atmel_st_timer_init);